Electric system



Sept. 14, 1948. H. E. EDGERTON Laval /2 K Sept. 14; 1948. H EDGERTQN 2,449,063

ELECTRIC SYSTEM Filed Nov. 19, 1943 2 Sheets-Sheet 2 Ma a I A discharge-condenser means is Patented Sept. 14,1948

'UNl-TED STATES PATENT OFFICE memo s s'rau Harold a. Edger-ton. Belmont, Mass. Application November 10, 194:, Serial No. 510,98 1': claims. (01. 111-32) The present invention relates to electric systems. and more particularly to flash-producers. From a more specific aspect, the invention relates to flash-producing beacons; such as are used at airflelds to signal or otherwise attract the attention of aviators in airplanes.

Present-day rway beacon lights are of the rotary beam type, which sweep a beam of light through a complete revolution in about ten seconds. The reflector that produces the beam is rotated mechanically at the top of a signal pole.

An object of the present invention is to produce a beam that apparently rotates, but without any moving parts except, possibly, for a simple timing circuit. Another object is to give the illusion of a beam of light traveling rapidly along some other configuration than in azimuth.

Since power at desired sites is often at a premium, another object is to produce a more efficient beacon.

A still further object is to provide a new and improved beacon that shall have a wider beam, in order that it may an incoming plane.

Another object is to provide a new and improved beacon that shall be capable of operating at higher flashing rates.

Another object is to provide a new and improved beacon that shall be reliable in operation.

Otherand further objects will be explained hereinafter, and will be particularly pointed out in the appended claims.

With the above ends in view, a feature of the invention resides in employing a number of flashlamps arranged according to a predetermined configuration, and illuminated rapidly, in predetermined sequence or succession, by discharging high-tension condenser means through the spaced flash-lamps, rapidly in predetermined sequence or succession. As all the energy of the thus expended, at any particular time, in producing a flash, highintensity flashes are short periods of time. The energy of the condenser means is replenished by charging it before each discharge thereof.' The number of' flash-lamps is sufficiently large and the flashing is sufllciently rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined conflguration. The incoming aviator is thus enabled to receive light flashes continually.

The invention will now be more particularly explained in connection with the accompanying drawings, in which Fig. 1 is a diagrammatic elebe more easily detected from thus produced for very Fig. 5 is a similar view According to the specific embodiments of the vation of a beacon embodying the present invention; Fig. 2 is a fragmentary perspective, with parts broken away; Fig. 3 is a view of one of the flash-lamps, the reflector in which it is mounted being shown in longitudinal section; Fig. 4 is a diagrammatic view of circuits and apparatus embodying the invention, in preferred form; and

of a modification.

invention that are herein illustrated and described, a number of flash-lamps is are spaced uniformly over the beacon throughout the 360 degrees of azimuth. The invention is applicable to other configurations also. In the illustrated configuration, however, the flash-lamps l8 are disposed along a circular row in a horizontal plane, within a housing having a cylindrical transparent wall i3, at the top of a beacon support 8. 'Each flash-lamp is mounted in a reflector 25 for directing the light of that particular flash-lamp along a particular direction of azimuth. The flash from the lamp positioned at A, for example, may be directed south, in which event the flash from the lamp positioned diametrically opposite, at B, may be directed north. The flashes from the lamps positioned at C and D'may similarly be directed east and west, respectively- Two flash-lamps positioned at E and F, on opposite sides of, and adjacent to, the flashlamp positioned at A, will direct flashes in corresponding directions: the lamp positioned at E will direct a flash between south and south-east, and the lamp positioned at F will direct its flash between south and south-west. The lamp positioned at G will produce a flash in a direction between east and south-east, and the lamp positioned at H in a direction between west and south-west. The lamps positioned at J K, L and M will send their flashes in directions opposite to the directions of flash of the lamps positioned at G, E, F and H, respectively. As many lamps as desired may be provided, each with a reflector for directing the flash in a particular direction of azimuth. It is convenient to employ also a further flash-lamp, shown positioned at I, for directing its flash upward through a transparent portion 32 of the upper wall 33 of the housing at the top of the support 8. This lamp is particularly useful in fo gy weather.

Each flash-lamp i8 is of the gaseous-discharge type.. The flashes through the flash-lamps it are produced by discharging therethrough the electric energy stored in high-tension dielectric electric-energy-storage or condenser means, illustrated as a condenser H. The condenser means constitutes the principal source of energy for etfecting the discharge of the flash-lamps; it is first charged and then discharged through the flash-lamps I8 rapidly, in predetermined sequence or succession. surges of current are thus caused to flow rapidly, in predetermined sequence or succession, through the flash-lamps l8. Each surge of current produces a flash of high intensity in the corresponding flash-lamp i8, followed by prompt extinguishment of that flash-lamp l8 l0 and the flashing of the next flash-lamp ll, Lu predetermined sequence, or succession. Each flash-lamp I8 is thus rendered momentarily luminescent, to produce a flash, by. the discharge oi the condenser means therethrough. 1

Assuming, for example, that the flash-lamp positioned at C is the first to flash, the next lamp to flash will be that positioned at G, then the lamp positioned at E, then the lamps positioned at A, I", H, D, J, K, B, L and M. The lamp positioned at I will finally be flashed, after which the other lamps will be again flashed in succession, in the same order. 7

Let it be assumed that the incoming aviator is directly south or the beacon, and at a considerable distance therefrom. He may, in that event, observe at least the flash from the lamp positioned at A. That single flash alone will guide him to the airport. By reason of the fact that the whole energy of the condenser ii is concentrated, at the time of the flash, in that one lamp, the flash will be of considerable in-- tensity, with the result that he may see it at a very great distance.

As he approaches closer, the flash from the lamp positioned at A will become more intense, and he may begin to see also, though with less intensity, the flashes from the lamps positioned at E and F. As he comes closer still, he may see the flashes of other lamps also, say the lamps positioned at G and H.

The same remarks apply no matter from what direction the aviator arrives. There will always be at least one lamp flashing along his direction, or nearly so, with the greatest intensity, and perhaps other lamps flashing in slightly difierent directions with less intensity.

The successive flashing of the lamps along different directions of azimuth, moreover, gives the illusion of a rotating beam of light, but without the necessity for employing moving parts. The same applies to any other configuration, the nature of the illusion of the beam of light traveling from flash-lamp to flash-lamp depending upon the nature of the configuration. In the event of dense fogs or other weather conditions that would render these flashes not readily perceivable, the upwardly directed flash from the lamp positioned at I would become more visible from the reflection of the fog or other atmospheric conditions.

The preferred gaseous-discharge flash-lamp I 8 may contain xenon or other suitable gas. It is shown mounted in an elongated light-permeable glass-bulb jacket or envelope 92, which is shown cemented at 24 to a fiat insulating base 94, pro- 05 vided with three terminal pins 6, i2 and it pro- Jecting exteriorly thereof. 7

The reflector 25 is mounted upon the base 94.

It may, for example, concentrate the light into a cone of approximately 30 degrees. Light so concentrated would-be visible at a greater distance than the light from the same lamp without a reflector.

The flash-lamp I8 is shown provided with a cathode 1 and an anode 8, respectively connected 4 to the terminals 0 and ii. A high-voltage-spark trigger or trip wire control starting electrode 22 is connected to the terminal ll.

Each flash-lamp II is shown connected, through the medium or the terminal pins l1 and 8, across the discharge condenser II. The terminal pins I! are connected to a grounded terminal II, at one side or the storage condenser by.a conductor 3|, and the terminal pins 0 are connected to a terminal II, at the other side of the condenser II, by a common conductor II.

The electric-energy-storage condenser Ii may be subjected to a voltage 01', say, 2000 volts, from any direct-current supply. The preferred supply 5 is shown as a transformer 26.

the primary winding 20 of which may be connected to any desired source of alternating energy of suitable voltage and frequency, and the secondary winding 30 of which may be connected to the condenser,

ll through a full-wave rectifier 12. This conveniently provides a supply or pulsating current for charging the condenser'l I. The secondary winding 30 may have a high impedance for performing the normal current-limiting function of a charging impedance.

A motor 34 is'illustrated as the. motive power for driving a commutator, switch, having as many commutating cams 38, ll, M, or III, I, IBI, as there are flash-lamps I! to be flashed. The eommutating cam I9 is designed to close a switch 62. the cam 40 a switch 81, and the cam 8! a switch 64. The commutating cams I", 0, I6i are similarly designed to close switches I82, I63, 184. These switches will become momentarily closed, in sequential succession, by the corresponding cams, in response to the operation of the motor 34, and then will become reopened. The switches may be of the snap or toggle variety so that they may close with a positive action, to insure good contact in a short interval of time.

The voltage to which the condenser means is subjected by the direct-current voltage supply before each discharge thereof is insuflicient to cause the condenser means to discharge between the cathodes l and the anodes 9 through the normally non-conductive flash-lamps it, when nonconductive, notwithstanding the connection of the condenser means to the flash-lamps 18. The flash-lamps is are rendered conductive, however. to control these discharges under the control of the starting electrodes 22. The starting electrodes 22, in turn, may be energized in any desired manner, as by means of normally ineflective trigger-discharge circuits operable, when effective, to render the flash-lamps l8 conductive irrespective of the state of charge of the condenser means. This will now be explained.

In the system of Fig. 5, condensers ll, 42, M are shown connected in respective trig er-discharge circuits to the terminals l3 and II, in parallel with the condenser H, by conductors II and B1. A resistor 58 is shown connected by the conductors 5i and 51 in series with the condenser II, a resistor 69 in series with the condenser 42, and a resistor 60 in series with the condenser 43. The condensers of Fig. 5 are all connected to the direct-current source by way of the terminals II and ii.

In the system oi Fig. 4, however, the corresponding condensers ll, 42, 43 are shown connected by the conductorsili and I'l'across a common impedance, shown as the portion ll oi a bleeder resistor. One end or the bleeder-resistor portion 8i is connected to the terminal l3;

' of the transformer 38'is and the other end, through a portion III of the bieeder resistor, to the grounded terminal I5. The bleeder-resistor portions 8| and I8I are thus connected in series across the direct-current puisating-energy supply 28, 12. The condensers 4|, 42, 43 of Fig. 4 are therefore supplied with voltage, to store electric energy therein, ultimately from the same direct-current-power supply that charges the condenser II, but directly fromthe bleeder-resistor 8|, which constitutes their main power supply.

The condenser II may be discharged through the respective discharge tubes I8, as more fully explained hereinafter, by means of separate trigger circuits. The motor-driven commutator switch eflects a current flow through the separate trigger circuits, in predetermined sequence, to energize the triggering transformers in succession, thus to energize the trigger electrodes 22 of the flashiamps I8 in succession. High-voltage separate triggering sparks are thus produced to effect a discharge of the electric-energy-storage condenser iI through the corresponding luminescent-discharge devices I8, in succession. This is effected through the medium of separate triggering transformers, three of which are shown at 38, 48 and 58. Each lamp I8 is provided with one such triggering transformer. The transformer 38 is shown provided with a primary winding 14 and a secondary winding 38; the transformer 48 with a primary winding 41' and a secondary winding 48; and the transformer 58 with a primary winding 54 and a secondary winding 55. One side of each of the secondary windings 38, 48, 55, is connected to the terminal I3 by the conductor 29. The other sides of the secondary windings 38, 48, 85 are respectively connected to the termirials M of the triggering starting electrodes 22. A separate trigger circuit is thus provided for each control electrode 22. The connections of the primary windings of the transformers are not the same in the systems of Figs. 4 and 5. Referring first to Fig. 5, theprimary winding 14 shown connected across the condenser M, in series with the switch 82, by a conductor 9|; the primary winding 41 of the transformer 48 is similarly shown connected across the condenser 42, in series with the switch 83; and the primary winding 54 of the transformer 58 is similarly shown connected across the condenser 43, in series with the switch Each condenser 4i, 42, 43 is thus connected in its discharge circuit with the primary winding of its transformer. Similar connections to the additional flash-lamps I8, not shown, will be made through similar transformers, not

shown.

According to the preferred embodiment of the invention shown in Fig. 4, however, the condensers 4|, 42, 43 are connected to the respective primary windings 14,. 41, 54 by means of triggering circuits comprising normally ineffective, because non-conducting, thyratrons or other gaseous-discharge trigger tubes I, IIII, I02, connected in series with the condensers H, 42, 43 and with. the primary windlugs 14, 41, 54. A preferred trigger tube may be of the cold-cathode gaseous-discharge type illustrated and described in Letters Patent 2,185,189, 2,201,166 and 2,201,167, issued to Kenneth J. Germeshausen on January 2 and May 21, 1940. It may comprise an evacuated glass envelope containing several electrodes, namely,

' thereof.

-. ger-condenser-discharge a solid cold cathode 2, an anode or plate 5 and one or more control electrodes 3. With tubes of this type, the current required by the switches I82, I33, I54 becomes nbgligible, and 'wear due to arcing is thereby reduced, so that long life is enjoyed. An impedance is shown connected between the cathode 2 and the control electrode 3. The discharge circuits of the condensers II,

42, 43 thus contain the respective tubes I, "ll, I02 and the respective primary windings. These tubes I, IIII, I82 may be operated in succession, in response to the closing of the switches I82, I83 I84, respectively, as hereinafter more fully described, to discharge through the respective primary windings 14, 41,

. 54, thereby to flash their respective flashlamps I8 at the desired instants.

In operation, in the systems of both Figs. 4 and 5, the condenser II starts to become charged from the direct-current source 28, 12. The tube I is at this time non-conductive; The condenser 4| becomes charged, at the same time, through the resistor 8| and the primary winding 14; In the system of Fig. 4, upon the momentary closingof the switch I82, by the commutator cam I88, the potential of the control electrode 3 of the tube I becomes raised until the breakdown voltage between'the control electrode 3 and the cathode is exceeded, whereupon the trigger tube I becomes conducting. The condenser H, which has previously become charged from the rectifier supply 28, 12 of pulsating current, then discharges through the previously-described trigcircuit comprising the tube I and the primary winding 14. The same discharge of the condenser 4i, through the primary winding 14, takes place in the system of Fig. 5 upon the momentary closing of the switch 82 by the commutator cam 38. In both systems, the resulting voltage-surge pulse of the secondary winding 38 of the transformer 38 will thereupon become applied to energize the trigger electrode 22 of the corresponding flash tube I8; this tripping of the trigger-discharge circuit for the condenser 4I will cause the gas in the corresponding flash-lamp I8 to become ionized, producing a conducting path through the corresponding luminescent-discharge device I8, and permitting the condenser II to discharge therethrough, between the cathode 1' and the anode 8 The resulting high-voltage discharge through this lamp I3 will produce a very brilliant flash of light of short duration. When the condenser II becomes fully discharged, this lamp I8 becomes extinguished, and the condenser II again becomes charged from the rectifier.sup-

ply 28, 12 of pulsating current, prior to its next discharge through its flash-lamp I8.

The switch 83 or I83 becomes thereafter momentarily closed, to effect a similar discharge, in similar manner, of the condenser 42 through the primary winding 41 of the transformer 48. The secondary winding 48 of the transformer 48 will thereupon similarly energize the starting elec trode 22 of the next lamp I8 to be flashed.

Upon the extinguishment of this next lamp I8, the next commutating cam will effect the closing of the next switch; and soon, until the cam 8| or I8I operates the last switch 84 or I84, whereupon the last condenser 43 will discharge'throughthe primary winding 54 of the transformer 58. The secondary winding 55 will thereupon effect a discharge of the condenser II through the last lamp I3, thus causing the flashing of this last lamp I3,

ergized, in very rapid succession, in this manner,

to cause the flash-lamps it to become flashed very rapidly in succession, as before described. The flashing cycle will then recommence.

Instead of employing the switches in, its and i6 3, the tubes 8, Iii, M2 may be controlled through the medium of well known elec trical time-delay circuits for rendering each lamp responsible for starting the succeeding lamp after a predetermined time delay.

In accordance with the present invention, therefore, a very edective beacon is provided, far more powerful than present-day beacons, yet requiring less power and maintenance, and employins only a single small condenser ii for providing the flashing energy in all directions, both in azininth and upward.

Further modifications will occur to persons skilled in the art and all such are considered to fall within the spirit and scope oi the present invention as defined in the appended claims.

What is claimed is:

i. a flash-producing system having, in combination, a. plurality of flash-lamps each provided with a cathode, an anode and a control electrode, each flash-lamp being provided with a transformer for energizing the corresponding control electrode, a condenser for discharging through the flash-lamps between the anodes and the oathodes thereof to cause the flash-lamps to flash,

means for charging the condenser beiore each discharge, and a motor-driven switch for enersizing the transformers in succession to energize the corresponding control electrodes in succession, thereby to discharge the condenser through the flash-lamps in succession.

2. la flash-producing system having, in combination, a plurality of flash-lamps each provided with a cathode, an anode and a control electrode, each hash-lamp bein provided with a transformer for energizing the corresponding control electrode, a discharge device for controlling the corresponding transformer, a condenser for discharging through the flashlamps between the anodes and the cathodes thereof to cause the flashlamps to flash, means for charging the condenser before each discharge, and means for controlling the discharge devices rapidly in succession to energize the transformers in rapid succession, thereby to energize the corresponding control electrodes rapidly in succession, whereby the condenser will be discharged through the flash-lamps rapidly in succession.

- 3. An electric system having, plurality of discharge devices each having a control electrode, the discharge devices being each adapted to produce a light flash in response to the discharge of energy therethrough, dielectric storage means constituting the principal source of energy for eilecting the discharge of said discharge devices and adapted to discharge substantially all the energy stored therein at each discharge, means for charging the storage means before each discharge, separate trigger circuits for the respective discharge devices, a plurality of storage means, one corresponding to each trigger circuit, and means for efl'ecting discharges of the plurality of storage means in the respective trigger circuits in a. predetermined sequence to control the respective control electrodes in order to eii'ect the discharge or energy through the respective discharge devices from the dielectric storase means in a predetermined sequence.

4. A flash-producing system having, in combiin combination, a

nation, a plurality of flash-lamps each provided with a cathode, an anode and a control electrode, condenser means for discharging through the flash-lamps between the anodes and the cathodes thereoi to cause the flash-lamps to flash, means for charging the condenser means before each discharge, and motor-driven switch means for energizing the control electrodes in succession, thereby to discharge the condenser means through the flash-lamps in succession.

5. A flash-producing system having, in combination, a support, a plurality of flash-lamps each provided with a cathode, an anode and a control electrode, electric-energy-storage means for discharging electric energy through the flashiamps between the anodes and the cathodes thereof to cause the flash-lamps to flash, the flash-lamps being spaced uniformly on the support in a horizontal plane and being provided with reflectors for directing their respective flashes along difierent directions of azimuth in the plane, means for storing electric energy in the electric-energy-storage means, and means for energizing the control electrodes in succession, thereby to discharge electric energy from the eiectric-energy-storage means through the flashlamps in succession, the number oi flash-lamps being sufiiciently large and the energizing means being operated rapidly enough to give the illusion of a rapidly rotating beam of light.

'7. An electric system having. in combination, a circuit including condenser means and a plurality of normally non-conductive discharge devices, means connecting the condenser means to the discharge devices to discharge the condenser means through the discharge devices when conductive, means for charging the condenser means before each discharge to a voltage insufficient to cause the discharge oi the condenser means through the discharge devices while non-conductive notwithstanding the connection of the condenser means to the discharge devices, normally ineffective means operable when effective to render the discharge devices conductive irrespective of the state of charge of the condenser means, and means for rendering the normally ineilective means eilective rapidly in sequence to render thedischarge devices conductive rapidly in sequence to discharge the condenser means through the discharge devices rapidly in sequence.

8. A light-fiash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flashlamps each adapted to produce light flashes in response to the discharge of electric energy therethrough when conductive, means connecting the condenser means to the flash-lamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means before each discharge to a voltage insuillcient to cause the discharge of the con denser means through the flash-lamps while nonconductive notwithstai'iding the connection of the condenser means to the flash-lamps, normally ineflective means operable when efiective to render the flash-lamps conductive irrespective oi the state of charge of the condenser means. and means for rendering the normally ineflective means eflctive rapidly in sequence to render the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence.

9. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flashlamps each provided with a cathode, an anode and a control electrode and each adapted to produce light flashes in response to the discharge electric energy therethrough between its anode and its cathode when rendered conductive under the control of its control electrode, means con necting the condenser means to the anodes and the cathodes of the flash-lamps to discharge the condenser means through the flash-lamps when conductive between the anodes and the cathodes thereof, means for charging the condenser means before each discharge to a voltage insuillcient to cause the discharge of the condenser means through the flash-lamps while non-conductive notwithstanding the connection of the condenser means to the anodes and the cathodes of the flash-lamps, and means for energizing the control electrodes rapidly in sequence to render the flash-lamps conductive rapidly in sequence to'discharge the condenser means through the flashlamps between the anodes and the cathodes thereof rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence. I

10. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally lamps each adapted to produce light flashes in response to the discharge oi! electric energy therethrough when conductive, each flash-lamp being provided with a transformer, means connecting the condenser means to the flash-lamps to discharge the condenser means through the flashlamps when conductive, means for charging the condenser means before each discharge to a voltage insufllcient to cause the discharge of the condenser means through the flash-lamps while non-conductive notwithstanding the connection of'the condenser means to the flash-lamps, and means for energizing the transformers rapidly in sequence to render the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence.

11. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flashlamps arranged according to a predetermined configuration and'each adapted to produce light flashes in response to the discharge of electric energy therethrough when conductive, means connecting the condenser means to the flashlamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means, and means for rendering the flash-lamps conductive rapidly in sequence to discharge the condenser means non-conductive flashthrough the flash-lamps rapidly in sequence, thereby to causethe flash-lamps to produce light flashes rapidly in sequence, the number of dashlamps being sufllciently large and the operation of the rendering means being suificiently rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined configuration.

12. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flash lamps arranged according to a predetermined configuration and each adapted to produce light flashes in response to the discharge oi! electric energy therethrough when conductive, means connecting the condenser means to the flashlamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means before each discharge to a voltage insufllcient to cause the discharge of the condenser means through the flashlamps while non-conductive notwithstanding the connection of the condenser means to the flashlamps, and means for rendering the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence, the number of flash-lamps being sufllciently large and the operation of the rendering means being sufllciently rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flashlamp following the predetermined configuration. 13. A light-flash-producing system having, in

, combination, a circuit including condenser means and a plurality of normally non-conductive flashlamps arranged according to a predetermined configuration each provided with a cathode, an anode and a control electrode and each adapted to produce light flashes in response to the dis- I charge of electric energy therethrough between its anode and its cathode when rendered conductive under the control of its control electrode. means connecting the condenser means to' the anodes and the cathodes of the flash-lamps to discharge the condenser means through the flashlamps when conductive between the anodes and the cathodes thereof, meansfor'charging the condenser mean-s before each discharge to a voltage insufllcient to cause the discharge or the condenser means through the flash-lamps while hon-conductive notwithstanding the connection ofthe condenser means to the anodes and the cathodes of the flash-lamps, and means for energizing the control electrodes rapidly in sequence to render the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamp between the anodes and the cathodes thereof rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence, the number of flashlamps being sufficiently large and the energizing of the control electrodes being sufliciently rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined configuration.

14. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flashl-amps arranged according to a predetermined configuration and each adapted to produce light flashes in response to the discharge of electric energy therethrough when conductive, each flash-lamp being provided with a transformer, means connecting the condenser means to the flash-lamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means before each discharge to a voltage insuificient to cause the discharge of the condenser means through the flash-lamps while non-conductive notwithstanding the connection of the condenser means to the flash-lamps, and means for energizing the transformers rapidly in sequence to render the flash-lamps conductive rapidl in sequence to discharge the condenser means through the flashlamp rapidly in sequence, thereby to cause the flash-lamps to produce the light flashes rapidly in sequence, the number of flash-lamps being suificiently large and the energizing of the transformers being sumciently rapid tov give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined configuration.

15. A light-flash-producing system having, in combination, a circuit including condenser means and a plurality of normally conductive flashlamps arranged according to a predetermined configuration each provided with a cathode, an anode and a control electrode and each adapted to produce light flashes in response to the discharge of electric energy therethrough between its anode and its cathode when rendered conductive under the control of its control electrode,

each flash-lamp being provided with a transformer for energizing the corresponding control electrode, means connecting the condenser means to the anodes and the cathodes oi the flash-lamps to discharge the condenser means through the flash-lamps when conductive between the anodes and the cathodes thereof, means for charging the condenser means before each discharge to a voltage insufficient to cause the discharge of the condenser means through the flash-lamps while non-conductive notwithstanding the connection of the condenser means to the anodes and the cathodes of the flash-lamps, and means for energizing the transformers rapidly in sequence to energize the corresponding control electrodes rapidly in sequence to render the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps between the anodes and the cathodes thereof rapidly in sequence, thereby to cause the flash-lamps to produce light flashes rapidly in sequence, the number of flash-lamps being sumciently large and the energizing of the transformers being sumciently rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined configuration.

16. A light-fiash-producing system having, in combination, a circuit including condenser means and a plurality of normally non-conductive flashlamps arranged according to a predetermined configuration and each adapted to produce light flashes in response to the discharge of electric energy therethrough when conductive, means connecting the condenser means to the dashlamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means before each discharge to a voltage insuflicient to cause the discharge of the condenser means through the flashlamps while non-conductive notwithstanding the connection A: the condenser means to the flash- D trigger-circuit means connected to the flash-lamps,\;and means for rapidly triggering the trigger circuit means to render the flashlamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps rapidly in sequence, thereby to cause the flashlamp's to produce light flashes rapidly in sequence, the number of flash-lamps being sumciently large and the triggering operation being sufilciently rapid to give the illusion oi .a beam of light traveling rapidlyfrom flash=lamp to flash-lamp following the predetermined configuration.

17. A light-flash-producmg system having..in

combination, a circuit including condenser means and a plurality of normally non-cond ":e flashlamps arranged according to a predeteri ,rjlned configuration and each adapted to produce light flashes in response to the discharge of electric energy therethrough when conductive, means connecting the condenser means to the flashlamps to discharge the condenser means through the flash-lamps when conductive, means for charging the condenser means before each discharge to a voltage insuflicient to cause the discharge of the condenser means through the flashlamps while non-conductive notwithstanding the connection 01 the condenser means to the flashlamps, separate trigger-circuit means connected to the respective flash-lamps, and means for cper-a-ting the separate trigger-circuit means rapidly in sequence to render the flash-lamps conductive rapidly in sequence to discharge the condenser means through the flash-lamps rapidly in seof flash-lamps being sufliciently large and the triggering operation being sufiicien tly rapid to give the illusion of a beam of light traveling rapidly from flash-lamp to flash-lamp following the predetermined configuration.

HAROLD E. EDGERTON.

REFERENfiES CITED The following references are of record in the file of this patent:

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